The present research proposal utilizes a combined experimental neuroanatomic and behavioral approach to analyze central nervous mechanisms in the processing of visual inputs and the interhemispheric transfer of visual information. The proposal is divided into two major parts. Part one involves the use of light and electron microscopic techniques in conjunction with visual conditioning procedures to study the normal CNS anatomy and behavior of the blind cave fish, Astyanax hubbsi, and its sighted ancestor, Astyanax mexicanus. These same methods will be used to study changes which take place in CNS anatomy and behavior subsequent to larval eye transplantation from A. mexicanus to A. hubbsi. Part two involves a study of interhemispheric information transfer in the cat, in which bihemispheric function of the connected hemispheres will be compared with bihemispheric function of the disconnected hemispheres. A complementary study of unilateral function is also described, in which an attempt will be made to discover whether hemispheric differences reported recently are quantitative or qualitative. Split-brain surgical procedures, in combination with successive reversal learning techniques, have proven most productive in past work, and will continue to be used here. BIBLIOGRAPHIC REFERENCES: Gulliksen, H. and T.J. Voneida: An attempt to obtain replicate learning curves in the split-brain cat. Physiological Psychology 3:77-85, 1975. Voneida, T.J.: Prolonged learning following tectal commissurotomy in the cat. Anat. Rec. 181:501-502, 1975 (Abstract). (Paper delivered at meeting of the American Association of Anatomists, April, 1975).